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J Virol. 2007 Jul;81(13):7069-76. doi: 10.1128/JVI.00115-07. Epub 2007 Apr 18.

The p110alpha isoform of phosphatidylinositol 3-kinase is essential for polyomavirus middle T antigen-mediated transformation.

Journal of virology

Tamara Utermark, Brian S Schaffhausen, Thomas M Roberts, Jean J Zhao

Affiliations

  1. Department of Cancer Biology, Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115, USA.

PMID: 17442716 PMCID: PMC1933267 DOI: 10.1128/JVI.00115-07

Abstract

Middle T antigen (MT) of polyomavirus is known to play an important role in virus-mediated cellular transformation. While MT has been extensively examined in spontaneously immortalized rodent fibroblasts, its interactions with cells of other types and species are less well understood. We have undertaken a cross-species and cross-cell-type comparison of MT-induced transformation in cells with genetically defined backgrounds. We tested the transforming abilities of a panel of MT mutants, Y250F, Y315F, and Y322F, that are selectively mutated in the binding sites for the principal effectors of MT--Src homology 2 domain-containing transforming protein, phosphatidylinositol 3-kinase (PI3K), and phospholipase C-gamma, respectively--in fibroblasts and epithelial cells of murine or human origin. We found that the Y315F mutation disabled the ability of MT to induce transformation in all cell types and species tested. While Y315F also failed to activate the PI3K pathway in these cells, genetic evidence has indicated Y315 may make other contributions to transformation. To confirm the role of PI3K, the PIK3CA gene, encoding p110alpha, the prime effector of PI3K signaling downstream from activated growth factor receptors, was genetically ablated. This abolished the transforming activity of MT, demonstrating the essential role for this PI3K isoform in MT-mediated transformation. The Y250F mutant was able to transform the human, but not the murine, cells that were examined. Interestingly, this mutant fully activates the PI3K pathway in human cells but activated PI3K signaling poorly in the murine cells used in the study. This again points to the importance of PI3K activation for transformation and suggests that the mechanism by which MT activates the PI3K pathway differs in different species.

References

  1. EMBO J. 2001 Nov 15;20(22):6327-36 - PubMed
  2. Oncogene. 2001 Aug 16;20(36):4951-60 - PubMed
  3. Nat Rev Cancer. 2002 Dec;2(12):951-6 - PubMed
  4. Cancer Cell. 2003 May;3(5):483-95 - PubMed
  5. Proc Natl Acad Sci U S A. 2003 Aug 5;100(16):9434-9 - PubMed
  6. Science. 2004 Apr 23;304(5670):554 - PubMed
  7. Cell. 1979 Dec;18(4):935-46 - PubMed
  8. Cold Spring Harb Symp Quant Biol. 1980;44 Pt 1,:271-83 - PubMed
  9. Nature. 1981 Aug 13;292(5824):595-600 - PubMed
  10. J Virol. 1981 Sep;39(3):673-83 - PubMed
  11. J Virol. 1981 Oct;40(1):184-96 - PubMed
  12. Nature. 1983 Jun 2-8;303(5916):435-9 - PubMed
  13. Nature. 1983 Aug 4-10;304(5925):456-9 - PubMed
  14. Proc Natl Acad Sci U S A. 1984 Feb;81(3):679-83 - PubMed
  15. EMBO J. 1984 Jan;3(1):73-9 - PubMed
  16. EMBO J. 1984 Mar;3(3):585-91 - PubMed
  17. Cell. 1984 Oct;38(3):767-77 - PubMed
  18. Nature. 1985 May 16-22;315(6016):239-42 - PubMed
  19. Proc Natl Acad Sci U S A. 1986 Jun;83(11):3624-8 - PubMed
  20. J Virol. 1986 Aug;59(2):384-91 - PubMed
  21. Nature. 1987 Jan 8-14;325(7000):171-3 - PubMed
  22. J Virol. 2006 Aug;80(15):7295-307 - PubMed
  23. Nat Rev Genet. 2006 Aug;7(8):606-19 - PubMed
  24. Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16296-300 - PubMed
  25. Cell. 1987 Sep 25;50(7):1021-9 - PubMed
  26. Cell. 1987 Sep 25;50(7):1031-7 - PubMed
  27. EMBO J. 1988 Dec 1;7(12):3837-44 - PubMed
  28. EMBO J. 1988 Dec 1;7(12):3845-55 - PubMed
  29. J Virol. 1989 May;63(5):2343-7 - PubMed
  30. Cell. 1989 Oct 6;59(1):55-65 - PubMed
  31. J Virol. 1990 Jan;64(1):105-12 - PubMed
  32. Cell. 1990 Jan 12;60(1):167-76 - PubMed
  33. Proc Natl Acad Sci U S A. 1990 Apr;87(7):2521-5 - PubMed
  34. J Virol. 1990 Sep;64(9):4454-61 - PubMed
  35. Mol Cell Biol. 1991 Apr;11(4):1988-95 - PubMed
  36. J Virol. 1991 May;65(5):2308-13 - PubMed
  37. Mol Cell Biol. 1992 Mar;12(3):954-61 - PubMed
  38. Oncogene. 1992 Oct;7(10):1979-87 - PubMed
  39. Am J Pathol. 1992 Dec;141(6):1409-25 - PubMed
  40. Mol Cell Biol. 1993 Nov;13(11):6889-96 - PubMed
  41. Nature. 1994 Jan 6;367(6458):87-90 - PubMed
  42. Proc Natl Acad Sci U S A. 1994 Jul 5;91(14):6344-8 - PubMed
  43. J Biol Chem. 1995 May 26;270(21):12331-4 - PubMed
  44. J Biol Chem. 1995 Dec 8;270(49):29286-92 - PubMed
  45. Proc Natl Acad Sci U S A. 1997 Jul 22;94(15):7954-8 - PubMed
  46. J Virol. 1997 Sep;71(9):6279-86 - PubMed
  47. Mol Cell Biol. 1998 Apr;18(4):2344-59 - PubMed
  48. Oncogene. 1999 Jul 29;18(30):4364-70 - PubMed
  49. Am J Pathol. 2006 Jan;168(1):310-20 - PubMed
  50. Nature. 2006 May 18;441(7091):366-70 - PubMed
  51. Cell. 2006 May 19;125(4):733-47 - PubMed
  52. Cell. 2000 Aug 18;102(4):407-10 - PubMed
  53. Mol Cell Biol. 2001 Mar;21(6):2203-12 - PubMed
  54. Oncogene. 2001 Nov 26;20(54):7908-16 - PubMed

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